docs(site): add the landing page, user guide and developer guide

.github/workflows/pages.yml

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+# Publishes the documentation site to GitHub Pages.
+#
+# The site is `site/`, whose pages are generated from `docs/` at build time, so
+# a push that changes either rebuilds it. The build uploads the site's output
+# directory and nothing else from the checkout.
+
+name: Publish pages
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'docs/**'
+      - 'site/**'
+      - '.github/workflows/pages.yml'
+  workflow_dispatch:
+
+# One deployment at a time, and never cancelled: a half-replaced site is worse
+# than a late one.
+concurrency:
+  group: pages
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Build the site
+    runs-on: ubuntu-latest
+    # The job that runs `npm ci`, and so third-party install scripts, can read
+    # the repository and nothing else. Publishing rights live in `deploy`,
+    # which checks out no code.
+    permissions:
+      contents: read
+      pages: read
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+          cache-dependency-path: site/package-lock.json
+
+      - name: Install the site's dependencies
+        working-directory: site
+        run: npm ci
+
+      - name: Build the site
+        working-directory: site
+        run: npm run build
+
+      - name: Configure GitHub Pages
+        uses: actions/configure-pages@v6
+
+      - name: Upload the site
+        uses: actions/upload-pages-artifact@v5
+        with:
+          path: site/dist
+
+  deploy:
+    name: Publish to GitHub Pages
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v5

docs/faq.md

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+# AkidaTag FAQ
+
+Short answers to the questions people ask first. The [user guide](user-guide.md) and the
+[developer guide](developer-guide.md) have the detail.
+
+## About the tag
+
+**What is AkidaTag?** A small board with a Nordic nRF5340 microcontroller and a BrainChip Akida
+AKD1500 neural processor, a microphone, an inertial sensor and Bluetooth Low Energy. The AI model
+runs on the board; the phone only shows what the board found.
+
+**What does it do out of the box?** It runs the keyword spotting demo: it recognises ten spoken
+words and reports each one to the BrainChip Connect app. The model is loaded before the tag ships.
+
+**Does it need the internet?** No. The tag talks to the phone over Bluetooth, and nothing in the
+demo leaves the phone. The app needs the internet only to download firmware and model files.
+
+**Is the battery included?** No. The box holds the board and its enclosure; there is no battery,
+camera or USB-C cable in it.
+
+**How do I turn it on?** With the power switch on the board. The green LED blinks slowly once it
+is ready.
+
+## Phone and app
+
+**Which phones work?** Android phones running Android 13 or later, with Bluetooth. BrainChip
+Connect is coming soon to the iOS App Store.
+
+**Where do I get the app?** Its Google Play listing,
+https://play.google.com/store/apps/details?id=com.brainchip.connect, is open for pre-registration.
+Google Play tells you when it is released.
+
+**Does the phone ask me to pair?** The firmware does not ask for a pairing code, so no pairing
+pop-up appears.
+
+**Can two phones connect at once?** No. One phone at a time. If the tag's green LED is solid,
+another phone is already connected.
+
+## Using the demo
+
+**Which words does it know?** `down`, `go`, `left`, `no`, `off`, `on`, `right`, `stop`, `up` and
+`yes`. Anything else is reported as silence or unknown and is not shown.
+
+**It does not hear me.** The tag's microphone is a quiet part. Speak clearly and close to it, and
+check that the Keyword Spotting card says _Active_.
+
+**What do the LEDs mean?** See [What the LEDs mean](user-guide.md#2-what-the-leds-mean). The short
+version: green blinking is ready, green on is connected, a red flash is a detection, red on steady
+is a failure.
+
+**Can it learn a new word?** The firmware can learn new words on the device, and every release
+attaches `akidatag-kws-edge-learning-model.zip` for that. Running a learning session from the app
+is not covered in this guide yet.
+
+**What does Factory Reset do?** Today it restarts the tag and nothing else. A full reset that
+erases the model and settings will come in a later release.
+
+**What does Power Mode do?** Nothing in this release. It is where a low-power mode to save
+battery will be switched on in a later release.
+
+## Updating
+
+**How do I update the firmware?** From the app, with a file from
+https://github.com/Brainchip-Inc/AkidaTag/releases. See
+[Update the firmware over Bluetooth](user-guide.md#6-update-the-firmware-over-bluetooth). A
+computer and the USB-C cable work too: [Firmware update over USB-C](firmware-update-over-usb.md).
+
+**The update did not install.** The tag only accepts firmware signed with the key it trusts. Use a
+file from a BrainChip release. Anything built from the source code is refused over Bluetooth and
+USB-C, by design.
+
+**I cannot load a model.** Older firmware predates the model transfer the current app uses.
+Update the tag to the latest release, https://github.com/Brainchip-Inc/AkidaTag/releases/latest,
+and try again.
+
+## Building your own
+
+**Can I build the firmware myself?** Yes. The source is at https://github.com/Brainchip-Inc/AkidaTag
+and the [developer guide](developer-guide.md) starts from a fresh clone. Read the caution in its
+section 9 first.
+
+**Will the tag accept my firmware?** Not over Bluetooth or USB-C: your build is signed with the
+public development key, and a tag from BrainChip trusts the production key. With a debug probe
+you can flash the whole image, after which the tag trusts your key instead. See
+[Signing, and which firmware a board accepts](developer-guide.md#8-signing-and-which-firmware-a-board-accepts).
+
+**Can I run my own model?** Yes, converted with the Akida tools and loaded like the demo model.
+[Models](developer-guide.md#7-models) explains the pipeline.
+
+## Help
+
+**Where do I ask?** For help, BrainChip's Discord at https://discord.com/invite/9bmd9g52vn. For a
+bug, an issue at https://github.com/Brainchip-Inc/AkidaTag/issues. [Support](support.md) says what
+to include.
+
+---
+
+© 2026 BrainChip Holdings Ltd. All rights reserved.

docs/index.md

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+# AkidaTag documentation
+
+AkidaTag is BrainChip's ultra-low-power AIoT platform: a Nordic nRF5340 microcontroller and a
+BrainChip Akida AKD1500 neural processor on one board, with a microphone, an inertial sensor and
+Bluetooth Low Energy. The AI model runs on the board itself, and the board reports to the
+BrainChip Connect app on your phone.
+
+## Start here
+
+| Page                                  | Read it if                                                                                     |
+| ------------------------------------- | ---------------------------------------------------------------------------------------------- |
+| [Quick start](quick-start.md)         | You just opened the box and want the demo running in a few minutes.                            |
+| [User guide](user-guide.md)           | You have an AkidaTag and want to run the demos from your phone with the BrainChip Connect app. |
+| [Developer guide](developer-guide.md) | You want to build the firmware, add a demo, or write your own application on this code.        |
+
+## Hardware
+
+| Page                                                             | What it holds                                                                   |
+| ---------------------------------------------------------------- | ------------------------------------------------------------------------------- |
+| [Datasheet](hardware/datasheet.md)                               | Electrical, mechanical and environmental characteristics of the AkidaTag board. |
+| [Technical specifications](hardware/technical-specifications.md) | The parts on the board, the interfaces between them, and what each one offers.  |
+| [System block diagram](hardware/block-diagram.md)                | How the parts of the board connect to each other.                               |
+
+## Firmware reference
+
+| Page                                                      | What it holds                                                                                                       |
+| --------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
+| [Environment setup](setup.md)                             | The Docker toolchain image, a local install as the alternative, and the nRF5340 DK bench with an AKD1500 PCIe card. |
+| [Firmware update over USB-C](firmware-update-over-usb.md) | Updating a board with nothing but its USB-C cable, through the bootloader's serial recovery mode.                   |
+| [BLE model transfer protocol](ble-model-transfer.md)      | The wire contract between the firmware and BrainChip Connect for loading a model.                                   |
+
+## Help
+
+| Page                                | What it holds                                                          |
+| ----------------------------------- | ---------------------------------------------------------------------- |
+| [FAQ](faq.md)                       | Short answers to the questions people ask first.                       |
+| [Support](support.md)               | Where to ask for help and what to include.                             |
+| [Release notes](release-notes.md)   | What each firmware release changed, and what each release file is for. |
+| [Open-source licences](licences.md) | The licence of the firmware and of the code it imports.                |
+
+## Downloads
+
+- Firmware releases: https://github.com/Brainchip-Inc/AkidaTag/releases
+- BrainChip Connect for Android: listed on Google Play at
+  https://play.google.com/store/apps/details?id=com.brainchip.connect, open for pre-registration.
+  Coming soon to the iOS App Store.
+- Model packages: `akidatag-kws-model.zip` and `akidatag-kws-edge-learning-model.zip`, attached
+  to every firmware release.
+
+## BrainChip Connect
+
+The companion app has its own documentation at
+https://brainchip-inc.github.io/BrainChip-Connect/.
+
+## More from BrainChip
+
+- AkidaTag on the Developer Hub: https://developer.brainchip.com/akida-tag/
+- Developer Hub sign-up: https://developer.brainchip.com/signup/
+- Community: BrainChip on Discord, https://discord.com/invite/9bmd9g52vn
+
+---
+
+© 2026 BrainChip Holdings Ltd. All rights reserved.

docs/licences.md

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+# Open-source licences
+
+## The firmware
+
+The AkidaTag firmware is licensed under the Apache License 2.0. The text is the repository's
+[LICENSE](../LICENSE) file, and the copyright is held by BrainChip Holdings Ltd.
+
+The repository's [NOTICE](../NOTICE) file is the authority on the code the firmware imports: for
+every component it records the upstream, the version, the paths, and the licence statement the
+files themselves carry. This page is the summary.
+
+## Code imported into the repository
+
+Everything imported lives under `src/deps`, committed rather than downloaded, so that a clone plus
+the toolchain image builds the firmware. `src/deps/VENDORING.md` says where each tree came from
+and how it is upgraded.
+
+| Component                    | Version                | Licence            |
+| ---------------------------- | ---------------------- | ------------------ |
+| Akida Engine                 | 2.17.0                 | Apache License 2.0 |
+| FlatBuffers                  | 2.0.8                  | Apache License 2.0 |
+| Kiss FFT, float-only variant | unrecorded; see NOTICE | BSD 3-Clause       |
+
+NOTICE also records three smaller items outside `src/deps`: the MFCC feature extraction adapted
+from Arm's ML-KWS-for-MCU (Apache License 2.0), five build and sample files that carry the nRF
+Connect SDK sample header (Nordic 5-Clause licence), and the keyword-spotting sample input
+derived from the Google Speech Commands dataset (Creative Commons Attribution 4.0).
+
+## Code the firmware is built against
+
+The firmware is built with nRF Connect SDK v3.1.1, which is not part of this repository. It
+brings the Zephyr RTOS and the MCUboot bootloader, both under the Apache License 2.0, and Nordic
+Semiconductor's own components under the Nordic 5-Clause licence. Their licence texts and notices
+ship with the SDK.
+
+## The app
+
+BrainChip Connect is documented separately at https://brainchip-inc.github.io/BrainChip-Connect/.
+
+---
+
+© 2026 BrainChip Holdings Ltd. All rights reserved.

docs/quick-start.md

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+# AkidaTag quick start
+
+Six steps from the box to a keyword detected on the tag. The [user guide](user-guide.md) has the
+detail behind each one.
+
+1. **Charge the tag.** Plug a USB-C cable into the tag; none is included.
+2. **Get the app.** BrainChip Connect is listed on Google Play at
+   https://play.google.com/store/apps/details?id=com.brainchip.connect, open for pre-registration.
+   Google Play tells you when it is released. It needs Android 13 or later, and is coming soon
+   to the iOS App Store.
+3. **Turn the tag on** with the power switch. The green LED blinks slowly when the tag is ready.
+4. **Connect.** Open the app, allow Bluetooth, tap `AkidaTag` in the device list, then **Connect
+   to Device**. The green LED stays on while the app is connected.
+5. **Run the demo.** On the **Select the Application** screen, tap **Run Application** on the
+   **Keyword Spotting** card and wait for the badge to say _Active_.
+6. **Say a word.** Speak clearly and close to the tag: `down`, `go`, `left`, `no`, `off`, `on`,
+   `right`, `stop`, `up` or `yes`. The red LED flashes and the word appears on the card with its
+   confidence.
+
+## The LEDs at a glance
+
+| What you see                 | What it means                          |
+| ---------------------------- | -------------------------------------- |
+| Green blinks slowly, red off | Ready, waiting for a phone to connect. |
+| Green on, red off            | The app is connected.                  |
+| Red flashes briefly          | A keyword was detected.                |
+| Green off, red on steady     | Something failed; see the user guide.  |
+
+## When it does not work
+
+- Nothing in the device list: check that Bluetooth is on, the app has its Bluetooth permission,
+  and the green LED is blinking. A solid green LED means another phone is connected.
+- No words detected: the tag's microphone is a quiet part. Speak clearly and close to it.
+- Everything else: [Troubleshooting](user-guide.md#9-troubleshooting) in the user guide, then the
+  [FAQ](faq.md) and [Support](support.md).
+
+---
+
+© 2026 BrainChip Holdings Ltd. All rights reserved.

docs/release-notes.md

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+# AkidaTag firmware release notes
+
+Firmware releases are published at https://github.com/Brainchip-Inc/AkidaTag/releases. Every
+release carries its full list of changes in its release body, taken from the repository's
+[CHANGELOG.md](../CHANGELOG.md), which is the authority. This page is the short version: what
+each release was for, what is known to be wrong with it, and what each attached file does.
+
+## Versions
+
+Versions follow MCUboot's `major.minor.revision+build` form, the version the tag's bootloader
+reads out of the image header. The build counter resets to `0` whenever `major.minor.revision`
+changes. The app shows the same version on its firmware update screen.
+
+## Releases
+
+| Release    | Date       | What it was for                                                                                                                                                                                              |
+| ---------- | ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `v1.2.0+0` | 2026-09-14 | Pre-release. The product rename from Spark to AkidaTag, firmware update over the USB-C cable with no probe and no button, a build that works from a fresh clone, and the Akida engine committed to the tree. |
+| `v1.1.1+0` | 2026-08-25 | Patch release fixing the two defects that shipped in `v1.1.0+0`: a model update over Bluetooth never completed, and the DK build did not compile.                                                            |
+| `v1.1.0+0` | 2026-08-25 | Pre-release. Power measurement and power control on the board, a rewritten keyword-spotting scoring path, and the first hardware-in-the-loop CI job.                                                         |
+| `v1.0.0+0` | 2026-04-07 | First alpha of the firmware platform.                                                                                                                                                                        |
+
+Releases before `v1.2.0+0` carry the product's earlier name, Spark, in their file names.
+
+### Known issues in `v1.2.0+0`
+
+- **A tag on `v1.2.0+0` cannot load a model from BrainChip Connect `v1.0.0+0`.** The app speaks
+  the block-by-block model transfer that landed on `main` after the release. Update the firmware
+  to the latest release, https://github.com/Brainchip-Inc/AkidaTag/releases/latest, before loading
+  a model.
+- **Turning Edge Learning on in the app restarts the tag.** Fixed on `main`; not yet released.
+
+### On `main`, not yet released
+
+- The block-by-block model transfer the app uses, with every write carrying its position and the
+  tag acknowledging what it has stored.
+- The edge learning toggle fault above.
+- The microphone gain set for keyword spotting.
+
+## What each release file is for
+
+| File                            | Use it for                                                                                                                                                              |
+| ------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `akidatag-<version>.signed.bin` | Updating from the app over Bluetooth, or from a computer over USB-C. The application image only, signed with BrainChip's production key.                                |
+| `akidatag-<version>-dfu.zip`    | The same image packaged with a manifest. The app accepts either file.                                                                                                   |
+| `akidatag-<version>.signed.hex` | The same image for a programmer that takes Intel HEX.                                                                                                                   |
+| `akidatag-<version>-merged.hex` | Flashing a board with a debug probe: the bootloader plus the application. This is the only file that changes which signing key a board trusts. See the developer guide. |
+| `SHA256SUMS.txt`                | Checking a download: the checksum of every file above.                                                                                                                  |
+
+Each release also attaches the model packages `akidatag-kws-model.zip` and
+`akidatag-kws-edge-learning-model.zip`; see [Load a model](user-guide.md#7-load-a-model).
+
+---
+
+© 2026 BrainChip Holdings Ltd. All rights reserved.